The present invention relates to a conveying apparatus which uses motor rollers to convey and detect an object being conveyed.
Conventional conveying apparatuses, such as, for example, accumulating conveyors, have a structure such that the conveying area is divided into a plurality of sections along the conveying path. When an object is conveyed onto a conveying section in the situation where another object temporarily rests in the conveying section located downstream from the conveying section, the object in the upstream conveying section is paused. Once to object in the downstream conveying section is moved out, conveyance of the object in the upstream conveying section is resumes. Thus, a plurality of objects are conveyed in succession while being prevented from coming onto contact with one another.
In order to detect objects that are being conveyed, such a conveying apparatus typically includes a detecting means which may use a photoelectric switch or include a switch that can be turned on or off by a rotatable free roller which is being pushed down by the weight of an object. Other conventional conveying apparatus have a structure such that an encoder incorporated in a rotatable free roller is caused to output pulses by the free roller that turns in the manner of slave rotation when an object passes thereon.
In order to detect objects, however, conventional conveying apparatuses require a special detecting means that is provided separately from the conveying device. Providing such a separate detecting means increases the number of parts and complicates the structure.
It is an object of the present invention to provide a conveying apparatus which overcomes the problem.
It is a further object of the present invention is to provide a conveying apparatus which is capable of carrying and detecting objects while having a simple structure that does not necessitate a special detecting means, but merely uses motor rollers.
Briefly stated, the present invention provides a rotation detection device in a motor roller of a conveying apparatus to detect changes in the rotation speed of the motor roller. When an object is moved from an upstream location of a conveyance path to the motor roller having the rotation detection device, the rotation detection device detects the presence of the object by measuring the slight variation in rotation speed of the motor roller. A control unit is provided to monitor the output signals from a plurality of rotation detection devices, arranged along the conveyance path. The control device independently adjusts the conveyance speeds of a plurality of independent conveyance portions along the conveyance path based upon these output signals. This system allows conveyance of a plurality of objects along the conveyance while avoiding one object from running into another object due to, for example, a delay at a particular point along the conveyance path.
According to an embodiment of the present invention, there is provided a conveying apparatus, comprising: at least a first motor roller and a second motor roller; at least a first motor unit and a second motor unit; the first motor roller and the second motor roller each having a roller portion rotated by the first motor unit and the second motor unit, respectively; the first motor roller and the second motor roller providing conveying means for conveying an object along a conveyance path; a rotation detecting unit providing a rotation detection signal by detecting rotation of each of the roller portion; and control means for monitoring the rotation detection signal, thereby detecting a position of the object along the conveyance path.
According to another embodiment of the present invention, there is provided a conveying apparatus, comprising: a conveyance path; the conveyance path being divided into a plurality of independent conveying sections; conveyance means for moving objects along the conveyance path; detection means for detecting the presence of the object at one of the plurality of independent conveying sections of the conveyance path; control means for adjusting a speed of each of the plurality of independent conveying sections, whereby the objects are prevented from contacting each other; and the detection means includes measuring means for measuring the conveying speed of each of said plurality of independent conveying sections, thereby detecting a slight variation in the conveying speed when one of the objects moves into one of the plurality of independent conveying sections.
A conveying apparatus according to an embodiment of the present invention includes motor rollers, each of which is provided with a motor unit, a roller portion adapted to be rotated by said motor unit, and a rotation detecting unit for detecting rotation of the roller portion and outputting signals representing results of detection. A conveying device is adapted to carry objects by using the motor rollers. A control means is adapted to monitor detection signals output from the rotation detecting units of said motor rollers so as to detect objects based on changes in rotation of the roller portions.
With the configuration as above, the conveying apparatus makes use of the rotation detecting units that is incorporated in each motor roller for the purpose of control of its speed in such a way that the apparatus monitors detection signals output from the rotation detecting unit of the corresponding motor roller. These rotation detecting units detect an object based on change in rotation of the roller portion, which occurs when the object reaches the roller portion.
A conveying apparatus according to a feature of the present invention has the control means adapted to detect an object by monitoring detection signals output from the corresponding rotation detecting unit while rotating the corresponding motor roller at a constant speed.
As described above, the conveying apparatus detects an object by monitoring detection signals output from the corresponding rotation detecting unit while rotating the corresponding motor roller at a constant speed. Even if a reduction gear element is incorporated in each motor roller, arrival of an object causes change of rotation of the roller a portion more easily than when the motor roller is at a standstill. Therefore, the conveying apparatus ensures reliable detection of an object even if the object is light in weight.
A conveying apparatus according to another feature of the present invention has the control means adapted to detect an object by monitoring detection signals output from the corresponding rotation detecting unit while rotating the corresponding motor roller at a detection speed that is lower than a given conveying speed at which objects are conveyed.
When detecting an object, the conveying apparatus monitors detection signals output from the corresponding rotation detecting unit while rotating the motor roller at a detection speed that is lower than a given, conveying speed at which objects are conveyed. As a result of this feature, an object that has been conveyed at a given conveying speed easily changes rotation of a roller portion when the object reaches the roller portion. Therefore, the conveying apparatus ensures reliable detection of an object even if the object is light in weight.
A conveying apparatus according to a further feature of the present invention has a control means adapted to either increase the rotation speed of the corresponding motor roller up to the conveying speed, or stop its rotation, when the control means has detected an object.
By controlling a motor roller so as to either increase its rotation speed up to the conveying speed or stop its rotation upon detection of an object, the conveying apparatus either moves or stops the detected object.
A conveying apparatus according to another feature of the present invention is a conveying apparatus wherein the conveying device is provided with a plurality of conveying sections arranged along the conveying path along which objects are conveyed. Each conveying section has at least one motor roller. The control means of the apparatus is adapted to rotate the motor roller of a conveying section at the detection speed when an object rests in the conveying section that is located downstream from said conveying section. When another object is detected at the former conveying section, i.e. the upstream conveying section, the conveying apparatus temporarily stops the object in the upstream conveying section, and moves the object in the upstream conveying section after the object in the downstream conveying section is moved out of the downstream conveying section.
By thus rotating the motor roller of a conveying section at the detection speed when an object rests in the conveying section that is located downstream from the conveying section, and, when another object is detected at the upstream conveying section, temporarily stopping the object in the upstream conveying section, and moving the object in the upstream conveying section downstream after the object in the downstream conveying section is moved out of the downstream conveying section, the conveying apparatus performs accumulation of objects that are being conveyed.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.